Radio tuning instrument



Oct. 19 1926. `1,603,550

s. D. LIVINGSTON RADIO TUNING INSTRUMENT Filed Dec. 2l,- 1922 5 Sheets-Sheet l mmmmlmiaummm 1922 5 sheets-sheet 2 \\\\w W \\\\w N@ 2 m. N 1 x: KM. \M\\ /f Oct. 19 1926.

S. D. LIVINGSTON RADIO TUNING INSTRUMENT Filed Dec. 21,

Oct. 19 1926. 1,603,550

s. D; LIVINGSTON RADIO TUNING INSTRUMENT Filed Deo. 21, 1922 3 Sheets-Sheet 5 Il. 2N

ment.

Patented oci. 19,1926.

UNITED STATES PATENT OFFICE STANLEY D. LIVINGSTON, OF YORK, N. Y., ASSIGNOR TO EISEMANN MAGNETO CORPORATION, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

RADIO TUNING INSTRUMENT.

Application tiled December 21, 1922. Serial No. 808,216.

My invention relates to instruments used in tuning radio circuits, and its. object, broadly stated, is to provide improved devices embodying distinctive features` of novelty with consequent advantages in construction and operation.

In radio receiving sets as heretofore constructed, the knobs for adjusting the variousl units within the box or cabinet are mounted on the front panel in such a Way that they protrude therefrom for their entire length or thickness. W'here double knobs are used, as in Vernier condensei's or Vernier rheostat-s, the smaller knob projects beyond the larger. These protruding knobs not only detract from the appearance and neatness of the receiving set as a whole, but they are frequently in the Way.l Thus, a previously adjusted knob is liable to be struck accidentally by the operator and moved out of adjusted position.

One of the features of my invention eliminates the foregoing objections and disadvantages of protruding knobs by means of a recessed or cup-shaped plate adapted to house the knob or other hand member of the instrulVhen this plate is secured over an opening in the front panel, the rotary hand member is practically flush with the panel. This flush mounting is applicable in all radio units requiring adjustment by means of a. rotary member,-such as variometers, Variocouplers, variable condensers and rheostats, potentiometers, and so forth.

In place of the usual round knob heretofore employed. for adjusting those instruments, I prefer to use a bar which is more conveniently and steadily gripped by the fingers, thereby permitting a delicate adjustment to be made more easily and quickly. A mark at one end of the bar acts asa pointer, which moves close to a scale on the rim of the disk. For instruments requiring a double adjustment-such as, Vernier condensers, Vernier rheostats, and the like- I provide the bar with a central recess adapted to receive a small knob, which is thus practically flush with the front of the bar. When the bar and knob are gripped as a single member, they rotate together,l but the knob is readily adjustable independently of the bar.y

' 'Another feature of my invention generally applicable 7 to various radio units, lis the mounting of the instrument on the cupshaped plate previously referred to. This plate is preferably made of metal and carries a bracket at the back for attaching thereto the out/er fixed frame ofthe instrument and all parts carried thereby. I prefer to provide the bracket with a shaft bearing for the rotatable element ofthe instrument. This provides a very simple and yet secure support for the entire instrument and makes it an easy matter to mount the same on a panel of the receiving set. The metal plate offers the additional advantage that, when grounded, it acts as a ca acity shield. The panel may, therefore, e of metal. v

Certain features of my invention are particularly applicable to variable inductance units like variometers and variocouplers, where a substantially spherical or partly spherical member rotates within the chamber of a fixed member. The rotary member is usuall called'the rotor, and the stationary mem er is termed the stator. As known to those who are familiar-with vsuch prior devices, the rotor comprises a hollow spherical segment or shell of insulating material on which is wound a coil of Wire. Heretofore, it has been the practice to mold this shell in two-halves separated in a plane at right angles to the axis of the segment; or, to put it different-ly, in a plane substantially parallel to the planes of the coil windings. This method of making the shell halves is objectionable for several reasons. For instance, it requires separate means for holding the shell parts together, and also requires the. separate insertion of metal bushings in the line of axial support. Then again, the shell halves as previously constructed, although spherical on the outside, 95

are cylindrical on the inside, thus possessing walls of considerable thickness, especially at the middle. Thick walls of dielectric material are objectionable in devices of this kind, as every radio engineer understands. 100

My new construction of rotor obviates the fore oing objections of prior devices. In mol ing the shell halves, I make the line of separation in a plane parallel to or passing through the axis of the spherical seg- 105 ment; which is the same as saying, in a '5 J plane substantiall at right les to the lanes oi the coi windings. n the. p re- .yet of suicient Referring specifically to the so-c'alled variocouplers, my invention provides certain advantages over rior instruments of that t As hereto ore constructed, variocoup ers have the primary win on the stator and the secondary windingon the rotor. The primary winding isv tapped at di'erent points, which connect to a se arate ta switch mounted 'on the panel. his switc ,is controlled by a knob which moves a connecting arm over al series of contacts. In

i my new construction of variocou ler, I do away with 'this outside tap switch y mounting the tap switch on the rotor itself as a art of the instrument. The rotor .winding v is preferably the primary, but it'may be the control-led secondary. In the referred form, the switch in m variocoup er is controlled by a knob nes in the bar which operates the rotor and which is housed in the vcup-shaped supporting disk previously mentioned. this way, the variocou 1er and tap switch become a singlel unit an are vmounted on the panel as a single piece of xpparatus.-

The fore ing and other eatures and advantages oomy invention .will be clearly understood from a detailed description of the accompanyin drawings, in whlch Figure 1 is a ront elevational view of a variocoupler constructed in accordance with m'rinvention; v

ig. 2 is a side elevation of the instrument shown in Fi 1 Fig. 3 'is a detached view, partly in section of the su orting late with its attache bracket oiinwhich thre frame of the variocoupler is mounted;

Fig. 4 is a rear perspective view of the su rting bracket;

ig. 5 is a longitudinal cross-section aproxiniately on line 5-5 of Fig. 2, lookingownwardly;

Fig. 6 is a transverse cross-section ap px-'oxnnately on line 6-6 ofFig. 2, showing the tap switch mounted onthe rotor;

Fig. 7 is a to plan view of the variocoupler shown in t e precedin tigres;

,Fig. 8 is a' rear view of t e ger bar by means of which the posi-tion of t e rotor is Fig. 9 is an inside view of one of the shell Y halves which constitute the frame or body of the rotor;

Fig. 10 is an inside view of the other halfof the rotor shell; l

Fig. 11 is a front elevational view ofa varibmeter embodying certain features ofy tor indicated as a whole by S, and a rotary member or rotor designed as a whole by R. Imight sayhere tthe drawin"Y show the instrument', substantially in fu size. 'Ihe frameor body of the stator,` in the particular instance illustrated, consists of a pair of complementary shells 1 and 2 which, when. fitted together, meet along -a line or plane 3 and form a hollow frame or su port. lhe inside of this frame forms a substantially spherical chamber C, within which the rotor v is operatively mounted. The shell members 1 and 2 are made of a suitable insulating` material, of which there are several kinds on the market for that purose. In practice I have made the stator rame of a composition commonly called bakelite, which may be molded thin and yet po sucient rigidity. The stator shell 1 is formed with a rib or .flange front, and has a rib or flange 5 at the rear end. Similarly, shell 2 has a front flan e In 6 and a rear ange 7. When the two she are assembled the rear flanges 5 and 7 fit to ether, as shown in Fig. 7, and receive bo ts 8 or other fastening means. The front ribs or ianges 4 and 6 of the stator are spaced apart to receive a flange or anges 9 projecting rearwardly from a plate 10. The proecting member or members 9 may be regar the base angles to 9 and 10, which are best s own'in Figs. 3 and 4, maybe cast in a single piece preferably of metal. For convenience shall 10 in `a direction at right -call this member a bracket, which I have 4 at thetpxlate e plane of the late. The parts ed as an arm or rib extending from I marked K. The anges 9 of bracket K have holes 11 arranged in ali ent with holes 12 in flanges 4 and 6 see Fig. 7), and through these aligned openings pass suitable fastening means. such as bolts 13. It will thus be seen that the shell or frame of the stator S is rigidly mounted on bracket K. j

This bracket is provided with a central hub or bushing 14 (see Figs. 3 and 4) arranged to pro'ect into an opening 15 in the stator S, as own in Fi 5. As will presently be explained,/the hu 14 forms the front bearing for the` rotor shaft. In the broader aspect of my invention, the particular construction yor conguration of the stator shell is immaterial, provided only that it properly cooperates with the rotor. When I speak of the stator chamber C as substantially spherical,` I use the expression in a loose sense to describe a chamber adapted to accommodate the rotor.

On the inside of the stator is mounted a winding 16, which will be referred to as the stator winding. The turns of wire which constitute this winding are laid against the inside wall of the stator frame or shell, as may be seen in Figs. 5 and 6. In the present instance, the winding 16 is the secondary, but in the broader aspect' of my invention this winding might be made the primary. The two ends 17 and 18 of the stator winding 16 -are electrically connected to a pair of binding posts 19 and 20, respectively, mounted on the stator, as best shown in Fig. 5. The ends 17 and 18 are led through openings 21 in the 'stator shell and are permanently secured to the binding posts 19 and 20. Thus, by simply clamping the ends of the proper conductors to binding posts 19 and 20, which are easily accessible, the winding is connected in the radio circuit. As seen from Figs. 5 'and 6, the stator winding 16 yis in two halves or sections, one half being on shell 1 and the other half on shell 2. These two coil sections are electrically connected together by a wire 22, which passes through openings 23 at the rear end of the stator shell (see Fig. 2). In this way, the two halves of the stator winding form in effect a single coil.

I will now describe the rot-or R, which is mounted within the chamber C of the stator. The body of the rotor` as herein illustrated, consists of a pair of shells 24 and 25, which are substantially semi-spherical in shape and, when lit-ted together, form a hollow spherical segment or what some might call a truncated sphere. Of course, I use these terms, not in their strict mathematical sense, but rather in a practical way to denote the general shape'of the rotor. The general contour of the complete rotor shell is such that it ts rather closely within the chamber C, of the stator, as may be seen from Figs. 5 and 6. Attention is called to the fact that the shell halves 24 and 25 are separated along a line or plane 26 (see Figs. 2 and 5), which may be described as passing through or parallel to the axis of the spherical segment. For the sake of clearness, I might explain that the axis of the rotor shell or segment is an imaginary line passing through the centers 27 of the circular openings 28 formed at diametrically opposite ends of the rotor shell. To assist in fitting the shell halves 24 and 25 together, I provide the edges of member 24 with a lug 29 and a recess 30, while the corresponding edges f the other shell rmember are provided with a recess B1 and a lug 32. When the two shell halves are fitted together, lug 29 snaps into recess 31 and lug 32 enters recess 30. After the rotor is thus fitted together, it is ready to receive a Winding 323, which consists of turns of wiring coiled on or around the outer surface of the shell. It will be observed that these coil windings are laid in planes substantially at right ano'les to the plane of separation of the shell ha ves 24 and 25, whereby these windings also serve as a means for securing the shell halves together. This is a decided advantage because it dispenses with separate fastening means which are necessary in rotors heretofore constructed. In these prior devices, the two sections of the rotor are separated along a plane roughly indicated by the dotted line min Fig. 5. As will be seen, the plane is substantially parallel to the planes of the coil windings of the rotor, so that additional fastening means are required in these prior rotors to hold the shell halves together. I dispense with these separate fastening means altogether by constructing the rotor shell as above described. It is clear that the plane of separation of the shell members 24 and 25 need not be in the direction indicated at 26, but may be in any direction substantially parallel to the axis.

27 or any plane cutting through the planes of the rotor coil winding.

There is another advantage in my new rotor shell. The shell members 24 and 25 are molded out of a suitable insulating composition, such as bakelite. Referring to Figs. 5, 9 and 10, it will be seen that shell member 24 has embedded therein a screwthreaded metal bushing 34, while the other shell member 25 has embedded therein a metal 'bushing When the shell halves are assembled, vthe metal bushings 34 and 35 are in axial alignment, as best shown in Fig. 5. In the process of molding the shell halves 24 and 25, the bushings 34 and 35 are preferably placed at the bottom of the steel molds, which are then charged. with the fluid or plastic molding material. When the shell half is taken out of its mold, the axial bushing .34 or 35 is firmly embedded in the molded material. This embedding of the metal bushing in a single opera-tion is not possible in rotors where the shell halves are separated in a plane passing through the axial supports of the rotor, as indicated by the dotted line --m in Fig. 5. In that case it was necessary to insert the metal bushings separately after the shell halves had been molded. Furthermore, in molding the rotor shell halves according to my invention, it is possible to make the walls of uniform thickness, or perhaps I should say thinness. As all elec-v trical engineers understand, it is desirable in these radio instruments to have the. dielectric materalas thin as possible, and I eol tion 41 of the supporting p ate secure this advantage in my rotor construction.

Although I have shown the rotor inv substantially spherical form, it is clear that itf may be desi ed in any other practical shape adapte to rotate in the stator chamber The rear HarigeV or rib 7 of the stator is formed with a hub portion 36, in which is fixed a hollow. metal glug or bearing 37, as shown in Fig. 5. T e bushing 35 of the rotor extends 1nto the bearing plug 37, which thus forms a rear su port for the rotor. The front support o theirotor is formed by a hollow shaft 38 which passes through the bracket K and rotor bushing .hat portion of the hollow shaft 38 which passes through the bushing 34 is screw-threaded to en age the screw-threads of the bushing 34, w ereby the shaft 38 is rigidly secured to the rotor for operating the same. A `nut 39 at the inner end of shaft 38 holds the latter rigidly connected to i the rotor.

The supporting bracket K on which th stator S is mounted, as previously described in detail, is secured to a plate indicated as a whole by'l). ably sha d out of s eet metal, consists of an annu ar rim 40 and a recessed or cu shaped portion 41 extending rearward y from the rim. The rim 40 has a number o holes 42 for receiving screws 43 or other fastening devices, by means of which the disk is secured to a suitable panel P. This anel may be the front wallof a box or cabinet containing the different units of a radio receiving set. The panel has an opening 44 through which extends the cu -sha ed 01re bracket K is secured to the rear wall of the cup-shaped portion 41 by screws 45, or other fastening devices, passin into holes 46 in the plate 10 of bracket Thus'it is seen that the entire instrument is supported on plate D. By virtue of this arrangement, it is a very simple and easy matter to mount the instrument in proper position on a anel. When I refer to the rim 40 as annu ar, I do not mean that its outer edge or boundary must be circular, for'it is vobvious that the geometric outline of the rim 40 is immaterial, as long as it provides afiange around the cup-sha ed-portion 41 for securing the plate D an all parts carried thereby to the sup rting panel. Also, it will be clear that in t e broader aspect of my invention' it is immaterial whether the rim 40 enga es the outer or inner side of the panel.- en the rim 40 is fastened against the outside of the panel, it may serve the additional" function of carrying a scale or index, as later ex lained.

o the outer end of rotor shaft 38 is secured'a linger piece which is shown in the This late, which is preferf come to that Lacasse may be employed. Thefshape of the finger bar 47 is such that it ts within the` recess 41 of late D, so as .to be substantially flush with t e rim 40. This does away w1th the objectionable protruding knobs of prior radio units, enhancing the neatness and compactness of the radio set in `which the instruvment is used. Although housed within a recess, the bar 47 is easil i d b the fingers. I refer a bar to); goipor sg'veral reasons. n the first place, the bar 47 is more easily and naturall grip d b the fingers than a knob, so t at a gioie ad'ustvment vof the rotor can be easil made. so, the bar itself acts as a pointer simply roviding a suitable. mark or indicator 4 at one end thereof to cooperatel with a scale 49 on the rim 40 of plate D. This is shown in Fig. 1. Another advantage of bar .47 is that it may be recessed to receive a smaller knob in instruments where a double adjustment is required, as in varicouplers, vernier condensersand the like. I will presently particular feature of my'invention.

In order to limit the rotary movement of bar 47 in either direction, I provide a stop pin 50, which may be in the form. of a setscrew fastened in the plate 10of bracket K and projectin into the recess 41 of plate D, -as shown in 1g. 5. On the rear face of'bar 47 are formed two slots 51 arranged to re.- ceive the stop pin 50 when the bar 47 reaches the limit of 1ts movement in either direction.

I will now describe the tap switch that is mounted on the rotor as a part of the instrument and is connected to different points in the rotor winding. Within the rotor shell is mountedan insulated disk 52, which may be curved or dished to conform generally to the spherical contour of the rotor shell. The disk 52 has a non-circular openin 53 adapted to fit over a correspondingly s aped extension 54 of the rotor shell member 24, as shown in Fig. 5. The nut 39 holds the disk 52 firmly in position. If desired, a metal plate 55 may be interposed between the nut 439 and the disk 52. On the insulating disk 52 is mounted a series of metal contacts 56. In the present instance, I have shown eight of these contacts, but the number may vary. To. each contact 56 is electrically connected one end of a conductor 57.4 The other ends ofconductors 57 are connected to different points in the rotor winding 33, which is here assumed to be the primary winding. In order to enlao able this tapping of the rotor winding by means of conductors 57, I provide the rotor shell member 24 with holes 58, as best shown in Fig. 9. Portions of. the rotor winding protrude through holes 58 and thus permit connections to be made with the conductors 5T. Although there are eight switch contacts 56, with a corresponding number of conductors 57, it will be seen from Fig. 9 that there are nine o enings 58. This eX- tra opening is ,for tie pur ose of allowing a connection to be ma e between the two parts or sections of the rotor winding by means of a conductor 59, as indicated in dotted lines in Fig. 6.

Referring to Fig. 5, it will be seen that a rod 60 extends through the hollow rotor shaft 38. On the outer end of rod 60 is fixed a knob 61, which is held in position by a nut 62 or otherwise. The knob 61 is preferably housed in a recess 63 formed in l the central portion of the finger bar 47.

In this way, the knob 61 is mounted substantially flush with the finger piece 47 and does not pro'ect. beyond the rim 40 of the supporting plate D. On the screw-threaded inner end 64 of rod 60 is secured a switch arm 65 of good conducting material. .In Fig. 5, the switch arm 65 is shown clamped between a vpair of nuts 66. When the knob 61 is turned, the switch arm 65v moves over the contacts 56 andtaps the rotor coil at the particular point to which the engaged contact is connected. In order to enable the operator to determine how many sections of the rotor windin arev connectedin circuit, I. providev suitab e marks on the front o f the knob. In the particular con-l struction shown in the drawings, the rotor winding is tapped at eight points and so I place the numeralsl to 8 on the knob 61. The bar 47 has marked thereon an indicator 67, which acts as a stationa index for the numerals on the knob 61. or instance, in Fig. 1 the knob 61 is in such position that the indicating numeral 1 is opposite the mark 67. This means that the switch arm 65 is on the first contact 56, which would be the extreme right contact as viewed in Fig. 6. `When the indicating numeral 8 of the dial is opposite the mark or pointer 67. the switch arm 65 engages the last of the Switch contacts, as shown in Fig. 6. To limit the movements of switch arm 65 between the first and last of the contacts 56, I provide suitable stops 68, which may conveniently be made in the form of bent clips' secured to the first and last contacts. It will be clear that the contacts 56 and the arm 65 constitute a tap switch for the primary winding 33. l

It should be understood that the rod 60 is freely rotatable in the hollow shaft 38 without moving the rotor itself. After the tap switch has been .adjusted by turning the 05 knob 61, as explained, the o erator grips the bar 47 and knob 61 as i they were' a single member, and they turn as a unit to control the rotor. I needvnot explain that the object of turning the rotor one way or the other is to adjust the inductive relation of windings 16 and 33 because this point is well understood by radio engineers. It will be clear, then, .from what I have said, that when the rotor is adjusted, the tap switch mounted thereon moves with it as a part thereof, so that a previous adjustment of the switch is not disturbed.

By mounting the tap switch on the rotor as a part of the instrument, I dispense with the necessity of a separate tap switch outside of the instrument, as is required in the case o f variocouplers and other tuning instruments heretofore constructed. My new arrangement of tap switch not only simplifies the instrument and the receiving set as a whole, but adds to the neatness and compactness of the same. The nested arrangement of the finger bar 47 and switch knob 61 prevents these parts from protruding beyond the panel on which the instrument is mounted.

A binding post 69 is screwed into the metal bearing plug 37, asbest shown in Fig. 5, and bears against a coiled spring 70 mounted in the bushing 35 of the rotor. The

binding post 69 is intended to receive one end of the antenna wire. The spring 70 is of .conducting material and the outer end thereof is electrically connected to the leading-out wire 71 of the primary coil 33. The spring 70 is thus a yieldable conductor which insures a positive e ectric connection between one end of the primary coil and the binding post 69. The other end of the primary wind- 1ng 33 is grounded through switch arm 65, shaft 38, metal bracket'K and metal plate D, which is connected to the ground, as diagrzmmatically indicated at G Iin Figs. 2 an 5.

As I said before, I prefer to make the supporting plate D of metal. This not only gives a p ate of the required strength, but permits the plate to be grounded to the primary windlng of the instrument. This grounded plate acts as a shield against the capacit leffect of the operators hand or body, t ereby eliminating a disturbing factor in tuning the circuit.

In Figs. lland 12, I have shown what is commonly called a variometer. As many of the structural details of this instrument are substantially identical with corresponding parts in the variocoupler above described, I need not repeat a detailed description of these common features. In briefly describing Figs. 11 and 12, I will use the same reference characters as in the preceding to indicate like or corresponding arts, except that I will use prime marks ior the sake of distinction.

The stator S vis mounted on a bracketl K, which is secured tothe back of a supporting plate D', substantially in the manner previousl described in connection with parte S, K an D. Within the chamber of the hollow stator S operates a rotor B', which is controlled by a finger bar 47. The msulating shells or frameworks of the stator AS and rotor R are substantially the same as those of stator S and rotor R, referred to. On the inside wall o stator is mounted a winding 16', and on the outside of rotor R is a winding 33. As is usual in variometers, the two windings are connected together in series by conductors c and c', which pass through the bushin 35 of the rotor. One end o the connecte winding goes to a binding post 19 and the other to a binding post 20 What I have previously said about the advantages of the various novel features in the variocou ler applies equally well to the variometer sliown in Figs. 11 and'12, except that in the latter case no tap switch is required,

As I previously stated, in the broader aspect of my invention, the rotor coil mayI be the primary or the secondary. lheie are, however, certain advantages in makingthc rotor coil the primary. In variocouplers heretofore constructed, where the rotor coil is the secondary and where the primary is the stator coil to which a tap switch is connected, the adjusting of the-coupling between the two windings by turning .the secondary causes a disturbance in the adjustment of the inductive relation between the secondary of the variocoupler and such other l tuning units as are connected in the circuit or circuits ofv the secondary winding of the variocoupler. Such a disturbance of previously adjusted inductive relation is highly objectionable and undesirable, and makes the tuning complicated and diicult.

Now, in my invention, by making the rotor coil the primary, I eliminate the foregoing objection and difficulty because the position of the secondary winding of the variocoupler is-not altered with relation to the other units in the tuning circuit when the coupling between the variocoupler coils is adjusted by moving'the primary. This construction has the further advantage that it allows greater latitude in mounting the various tuning units of the entire outfit in relation to each other.

Although I have explained my invention in connection with a variocoupler and a variometer, it is clear that' certain features are applicable to all radio instruments requiring adjustment in tuning a radio receiving circuit, such as variable condensers, variable reviousy rheostats, potentiometer, and so forth. All

-of these and other devices used for like purunderstood that, `although I have herein shown and described certain s eciiic structures, it is obvious that the various features of my invention maybe mechanic y embodied in other forms than herein set forth.

I claim as my invention: 1. In radio tuning apparatus, a r

or cup-shaped supportin @plate provid with a surrounding rim w ereby said plate is adapted to be` mounted on a anel so as to be practically flush therewit a rotary hand member mounted in the recess of said plate, whereby said member is practically flush with the panel, an electrical device secured directly to said plate and supported thereby, and means foroperatively connecting said hand member with said device to control the saine.

2. In radio tuning apparatus, a recessed or cup-sha d supporting plate adapted to be mounte on a panel so as to be practically flush therewith, a pivoted bar 4mounted in the recess. of said plate, whereby said bar is practically flush with the panel, an elecs trical device secured directly to said plate and supported thereby, and means for operatively connecting said bar with said device to control the same.

3. In radio tuning apparatus, a supporting plate comprising a recessed or cupshaped portion surrounded by a rim having a scale, a pivoted bar mounted in said recessed portion of the late so as to be practicall fiush with-saidp rim, an indicator on said bar vto cooperate with said scale, an electrical device secured directly to .said plate and supported thereby, and means'for operatively connecting said bar with said device to control the same.

4. In radio tun' apparatus, a plate comprisin a recesse or cu -shaped portion surroundv by a rim .an adapted to be secured to a panel, a centrally pivoted bar mounted in said recessed portion of the plate so as to be practically flush with said rim, said bar having a central recess, a rotary knob nested in the recess of said bar, andA electrical devices independently controlled by said bar and said knob.

5. In ,radio tuning apparatus, a supporting plate comprising a recessed or cupshaped portion surrounded by a rim and adapted to be secured to a panel, a lurality of nested hand members coaxial y pivoted in said recessed portion so' as to be practically Hush with said rim, electrical devices secured directly to said plate and supported thereby, and connections between said hand members and said devices for independently controlling said devices.

6. In radio tuning apparatus, a plate comprising a recessed or cup-shaped portion sur-` rounded by a rim having a scale, a centrally recessed bar pivoted in said recessed portion of the late so as to be practically flush with sald rim, anA indicator on said bar to cooperate with said scale, a rotary knob nested in the recess of said bar and having a dial, a second indicator on said bar adapted to cooperate with said dial on the knob, and electricaldevices independently controlled by said bar and said knob.

7. As a new article of manufacture for supporting a radio tuning unit, a supportln plate adapted to be secured to a panel an comprising a recessed or cu shaped portion surrounded by a rim, sai recessed portion having a flat bottom or rear section of substantial area for attaching thereto a tunin unit.A

8. sa new article of manufacture for supporting a radio tunin unit, a one-piece sheet-metal plate adapte to be secured to a panel and comprising a recessed or cupshaped portion surrounded by a rim, said recessed portion havin a flat bottom or rear section of substantia area for attaching thereto a tuning unit.

9. In radio tunin apparatus, a plate adapted to be secure to a panel and having a recessed portion extending rearwardly, a variable tuning unit mounted on the recessed portion of said plate, and a hand member pivoted in said recessed portion for controlling said unit.

10. In radio tuning apparatus, a plate adapted to be secured to a panel and having a recessed portion extending rearwardly, a bracket secured to the rear wall of said recessed portion, a variable tunin unit mounted on said bracket, and a han mem ber ivoted in said recessed portion for con-v trol infr said unit.

11. fn radio tunin apparatus, a plate adapted to be secure to a panel and having a recessed portion extendmg rearwardly, a variable tuning unit mounted on the recessed portion of said plate, and a pair of nested hand members pivoted in said recessed portion for controlling said unit.

12. In radio tuning apparatus, a plate adapted to be secured to a panel and having a recessed portion extending rearwardly, a bracket secured to the recessed portion of said plate,a variable tuning unit mounted on said bracket, and a pair of nested hand members pivoted in said recessed portion for controlling said unit.

13. In radio tuning apparatus, a plate adapted to be secured to a panel, a bracket mounted on the back Wall of said plate and provided with a pair of rearwardly projecting lianges, and a tuning unit secured to said flanges.

14. In radio tuning apparatus, a plate adapted to be secured to a panel, a tuning unit mounted on the back wall of said plate, and a hand member extending through said plate for adjusting said unit.

15. In radio tuning apparatus, a plate adapted to be secured toa anel, a bracket mounted on the back wall o said plate, and a tuning unit secured to said bracket.

16. In radio tuning apparatus, a plate adapted to be secured toa panel, a bracket mounted on the back wall of said plate and provided with a pair of lrearwardly projecting flanges, a stator having flanges arranged to fit against the flanges of said bracket, fastening devices passing through both sets of flanges, a rotor within said stator, and means for adjusting said rotor.

17. In radio tuning apparatus, a plate adapted to be secured to a panel, a bracket mounted on said plate and provided with a bearing, a fixed tuning lelement secured to said bracket, a rotary tuning element associated with said fixed element and supported at one end in said bearing, and means for supporting the other end of said rotary element on said fixed element.

18. In radio tuning apparatus, a panel, a grounded plate mounted on the front of said panel, and a tuning unit mounted on Vthe back wall of said plate.

19. In radio tuning apparatus, a supporting panel provided with an opening, a metal plate mounted on the front wall of said panel and having a portion extending into said opening, a bracket secured to the back wall of sai plate, and a variable tuning unit mounted on said bracket said metal plate being grounded to act as a capacity shield.

20. In radio tuning apparatus, a supporting panel, a grounded metal plate mounted on the front of said panel, and a tuning unit back of said plate and having a winding electrically connected at one end to said grounded plate.

21. In Vradio tuning apparatus, a panel., a metal plate on the front wall of said panel, a variable radio unit back of said panel, and a rotary hand member mounted in 'front of said plate for controlling said unit, said plllat.d being grounded to act a's a capacity s 1e Q2. In radio tuning apparatus, a variable l tuning unit, an adjustable hand member for controlling said unit, a grounded metal shield between said unit and said hand member, and means for attaching said unit to said shield, whereby said shield forms a supportl for said unit.

23. In a radio tuning unit, an insulating shell having substantially the shape of a hollow spherical segment, said shell consisting of two complementary halves separated in a plane substantially parallel to the axis of the segment.

24. In a radio tuning unit, an insulating shell having substantially the shape'f of a hollow sphere with diametrically opposite sections cut away, said shell consisting of two complementary halves se arated in a 'plane which passes through t e planes of said cutaway sections.

25. In a radio tuning unit, a substantially spherical insulating shell consisting of two com lementary ha ves, and a coil mounted on the outer surface. of said shell, said shell halves being separated in a plane which cuts through the turns of the coil, whereby said coil binds the shell halves together.

26. In a radio tuning unit, a substantially sphericalshell of insulating material havin axially aligned metal bushin s embedde therein, said shell consistin o two complementary halves separated a on diametricall opposite lines lying in a p ane substantially at right angles to the axis of said bushings.

27. In radio tuning apparatus, a supporting panel having an opening, a recessed or cupaped plate mounted on the front of said panel and projecting rearwardly into said opening, a' stator supported on said plate and carrying thesecondary winding, a rotor movable within said stator and carrying the primary Winding, a tap switch mounted on said rotor and connected to the primary winding, a pair of rotar hand members concentrically mounted. at t e front of said lat-e so as to be substantially flush therewit p, a connection between one of said members and the rotor, a connection between the other member and said switch, said connections being such that said switch is adjustable independently of the rotor and that said rotor and said switch are rotatable as a unit. y

28. In radio tuning apparatus, a supporting panel having an opening, a recessed or cup-shaped plate mounted on the front of said panel and projecting rearwardly into said opening, a stator secured tothe back wall of said plate and carrying the secondar v winding, a rotor movable within said stator and carrying the primary winding, a tap switch mounted on said rotor and connected to the primary winding, a hollow shaft for operating said rotor, a recessed bar mounted substantially flush in said cupshaped plate and connected to the outer end of said shaft, a rod extending through said shaft, an arm at the inner end of said rod and arranged to engage said switch contacts, a knob nested in the recess of said bar and connected to said rod, said knob being rotatable vindependently of said bar, a scale on said knob, and an indicator on said bar for said scale, said bar and knob being rotatable as a single member. 29. In radio-tuning apparatus a supporting plate adapted to be secure tov a substantialliy 'plane of said upr' ht panel, 4a t unit mounte in a slgbstantially horizontal position on the back wall of'said late, and a hand member extending throng said plate and panel for adjusting said unit from tlie front of the anel.

80. In a ra io tunin apparatus, the combination with a pane having an opening, of a plate having` a rim adapted to be secured to the outer side `of said panel and also having a recessed or cup-'shapedy portion projecting rearwardly through said openin and a tuning unit secured to said recesse portion so as to extend rearwardly of said panel.

31. In radio timing apparatus, the combination with a panel having an opening, of a plate having a rim adapted to be secured to the outer side of said panel and also having a recessed or cup-shaped portion pro"'ectin rearwardlythrou h said opening, sai rim eing provided wit a scale, a variable tuning unit secured to said recessed portion so as to extend rearwardly of said panel, an adjustable hand member-in said recessed portion for controlling said unit and indicating means associated with' sai hand member to cooperate with said scale.

32. In a radio-receiving set, the combination with a supporting panel having an opening, of a. plate having a flange or rim adapte to lit against the outer wall of said panel for mounting said.` plate on the panel, an extension on said plate projecting through said opening, and a tuning unit secured to said extension.

33. In a radio-receiving set, the combination with a supporting panel, of a plate having a flange or rim ladapted to fit against the wall of said panel for mounting said plate on the panel, la variable tuning unit, means for attaching said unit to said plate in such osition that the unit extends inwardly rom' said =panel substantially at right angles thereto, and a hand member at the front of saidplate for controlling said unit.

34. In an electrical tuning unit, a stator consisting of two similar shell sections fitted together, the adjacent edges of said sections being provided with pairs of ears, a supporting member for said shell sections, said member comprising a plate provided with projections extending at right angles to the plate, said projectionsv bein arranged to fit etween the ears of said shel sections, and fastening devices passing through said ears and said projections for securing the shell sections together and to said plate, said plate being adapted to be securely fastened to a suitable support.

35. In radio tuning apparatus, the combination with a panel, of a tuning unit having a fixed part and a movable part, a separate bracket fastened to the fixed part of saidl unit and having a laterally projecting.,r supporting surface for receiving fastening means to secure the bracket to said panel, whereby said unit is supported in proper position on the panel, and a member at the front wall of said panel for manually adjusting said movable part..

3G. ln radio tuning' apparatus, a variable tuning' unit having a rotatable shait for varying' the electrical effect of said unit., and a separa-te bracket on said unit for securing' the saine to a panel in such position that said shaft extends practically at right angles to the plane ot the panel, said bracket having;` a laterally projecting suliiportingg,` surface to receive fastening means and thereby lirinly secure the bracket and unit to the panel.

37. In an electrical tuningy unit, the combination otl a rotary knob and a rotary bar content-rically mounted -tor independent rotation, said bar being recessed to receive said knob, an electrical member operated by said knob, and an electrical member operated by said bar.

38. ln an electrical tuning' unit, the conibiiiation of a rotary knob and a rotary bar concentrically mounted 'tor independent rotation, said bar bein; y recessed to receive said knob, means whereby said knob and said bar are rotatable as a unit, means whereby said knob is rotatable independently of said bar, an electrical member operated by said knob, and anelectrical member operated by said bar,

39. In an electrical tuning unit, the coinbination of a rotary knob and a rotary bar concentric-ally mounted for independent rotation, said bar being' recessed to receive said knob, means whereby said knob is rotatable independently ot said bar, an electrical member operated by said knob, an electrical member supported by said bar, an outer dial for said bar, and a dial on said knob arranged to cooperate with an indicating mark on said bai:

40. In radio tuning' apparatus, a supporting bracket comprisingl a base whereby the bracket may be mounted on a panel, a hub e.\tendiii;` from said base, an arm projectin g from said base, an electrical member secured to said arm, a. rotary sha lt extendingg` through said hub, and a second electrical member rotatable by said shat't.

4l. As a new article ot manufacture 'tor use in radio tuning apparatus, a supporting bracket consisting ot a. single castingY coni prising' a. base whereby the bracket may be secured to a panel, a hub extending' l'roin said base substantially at right angles to said baseand an arm proJecting .trom said base, for the purposes specified.

42. A device of the character described,

comprisingl a bracket .includingA a tubular member terminating at its one end in a supported by the shalt and within the trst coil.

STANLEY D. LIVINGSTON.

named 

